Re: [APML] OT: Infrared M13

OT or not Wei-Hao, that is a great image. Thanks for sharing!

Gary

----- Original Message -----

From: Wei-Hao Wang

To: APML

Sent: Sunday, July 03, 2005 6:07 AM

Subject: [APML] OT: Infrared M13

Hi,

Sorry for this OT. It's not a film image. I know there is a CCD list
but this is not
a CCD image. I know there is a DSLR list but this is not a DSLR image either.

This is M13 taken by a CMOS-like, 16 mega pixel mosaic camera. This camera
is still the largest near-IR camera in the world. I took images using
1.6 um and
1.2 um broadband filters but I only managed to process the 1.6 um data. So
I only have a B/W image. Telescope is our 2.2m telescope. Exposure time is 26
minutes at the center of the image and 8.7 minutes at the corners. Seeing was
about 0.7 arcsec. No deconvolution. Here are the 1.6 um B/W images:

small version
http://www.ifa.hawaii.edu/~wang/misc/M13_ULB_H-small.jpg
larger version (1.1MB)
http://www.ifa.hawaii.edu/~wang/misc/M13_ULB_H.jpg

Well, some people may feel B/W images are a little boring. To colorize the
image, I downloaded 2MASS 1.2, 1.6, and 2.1 um images and made an LRGB
color image. L is my own 1.6um image, RGB are 2MASS 1.2, 2.1, and 1.6 um
data respectively. This is not an easy task because stars are almost colorless
in near-IR. I have to swap the order of 1.6 and 2.1 um images to make
the stars
have a little color. Otherwise all stars will look stupidly green.
In addition,
2MASS's resolution and depth are both much lower than my image. This is why
there are color halos around bright stars and the faintest stars
remain colorless.
Anyway, here are the color images:

small version
http://www.ifa.hawaii.edu/~wang/misc/M13_ULB_2MASS-small.jpg
larger version (1.3MB)
http://www.ifa.hawaii.edu/~wang/misc/M13_ULB_2MASS.jpg

Enjoy.

Wei-Hao

______________________________________________________________________
Wei-Hao Wang :)

Institute for Astronomy at University of Hawaii

Address:
2680 Woodlawn Drive         Personal Website:
Honolulu, HI 96822             http://www.ifa.hawaii.edu/~wang
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